An organic electroluminescence element (so-called organic EL element) is a light-emitting element having a structure in which at least one layer of a luminous organic layer is interposed between an anode and a cathode. In such a light-emitting element, by applying an electric field between the cathode and the anode, an electron is injected into a light-emitting layer from the cathode side and also a hole is injected into the light-emitting layer from the anode side, and the electron and the hole are recombined in the light-emitting layer, whereby an exciton is generated, and the energy generated when this exciton is returned to a ground state is emitted as light.
As such a light-emitting element, there is known a light-emitting element which emits light in a long wavelength range exceeding 700 nm (see, for example, JP-A-2000-091073 and JP-A-2001-110570).
For example, in a light-emitting element disclosed in PTL 1 and PTL 2, by using a material in which an amine serving as an electron donor and a nitrile group serving as an electron acceptor are allowed to coexist as functional groups in the molecule as a dopant of a light-emitting layer, the emission wavelength is shifted to a longer wavelength.
However, in the related art, an element which has high efficiency and long life could not be realized although the element can be made to emit light in a long wavelength range (in a near-infrared range) exceeding 700 nm. In addition, the realization of a light-emitting element which emits light in a near-infrared range and has long life as, for example, a light source or the like for biometric authentication for authenticating an individual using biological information such as a vein or a fingerprint has been demanded.
Further, for the purpose of increasing the efficiency and the life of a light-emitting element, for example, as disclosed in JP-A-2004-2297, as an electron injection layer, a layer containing an azaindolizine-based material has been proposed. However, also in this case, it cannot be said that the efficiency and the life thereof are increased sufficiently to be used as the light source or the like for biometric authentication.
An object of the invention is to provide a light-emitting element which emits light in a near-infrared range and has high efficiency and long life, and a light-emitting device, an authentication device, and an electronic apparatus, each of which includes this light-emitting element.